To facilitate early detection of breast cancer, women should perform breast self-examination monthly and obtain regular professional breast examinations. The proposed research will attempt to determine why women in the greater Detroit area do or do not perform these breast cancer detection behaviors. The research will be guided by theory and research in public health and social psychology and will focus on women's beliefs and knowledge and on the demographic variables of age, race, and socioeconomic status. The specific aims are (a) to identify the beliefs, knowledge, and other variables that are important predictors of breast cancer detection behaviors (b) to determine the level of those beliefs and knowledge in the general population and in target subpopulations, (c) to identify the sources of information about health that are used and trusted by women, and (d) to validate improved measures of health beliefs relevant to breast cancer detection behaviors. On the basis of the research findings, recommendations will be made for health education interventions to encourage performance of breast cancer detection behaviors. Specifically, recommendations will be made about what information to emphasize and about what channels of communication to use in interventions for the general public and for several target populations. Data will be collected in personal interviews with a probability sample of 700 adult women in the greater Detroit area. The breast cancer detection behaviors will be reassessed in a one year follow-up by telephone. Most predictor variables will be measured by multi-item scales which will have been pretested in pilot work. Multiple regression analysis will be used to determine which variables contribute to prediction when other variables are held constant.